A Maine group protesting the deployment of some 600,000 smart meters took its case back to the state supreme court, arguing the Public Utilities Commission erred when it found the wireless devices were not a threat to public health.

The Maine Coalition to Stop Smart Meters is appealing a ruling by the state Public Utilities Commission (PUC) last fall, which found no established connection between smart meters and health problems. The coalition claims that the meters can cause a number of health problems, including headaches, fatigue, loss of sleep and, potentially, cancer.

Central Maine Power Company (CMP), owned by the Spanish energy conglomerate Iberdrola, says that the radio waves emitted by the devices are well below standards set by the Federal Communications Commission, according to an article in The Portland Press Herald.

The hearing on November 2 was the most recent skirmish in a long-running dispute over the safety of the electronic devices that have largely replaced analog electric meters in Maine and elsewhere. Wireless smart meters allow utilities to track the distribution of electricity across the grid in real time and, at least in theory, give both consumers and utilities new ways of managing power consumption.

CMP originally won PUC approval for its $200 million conversion program in 2009. Critics took the PUC to court, and in 2012 the Maine Supreme Court ordered the PUC to revisit the issue. A PUC staff report delivered in March 2014 said that there were no credible studies linking the meters to ill health, and six months later commissioners voted to accept the staff report.

The coalition appealed, first with written arguments and then the brief oral arguments on November 2.

Just what are the threats?

The safety of smart meters in Maine and elsewhere is part of a larger debate over the possible health effects of exposure to the many wireless devices people routinely come in contact with — microwave ovens, cell phones, and wireless routers as well as smart meters — and the radio frequency (RF) radiation they produce.

Ed Friedman, the lead complainant in the Maine case, says that wireless technology represents “a public health and security emergency the likes of which we have never seen.” The coalition’s website refers to a half-dozen publications or reports dealing with the risks of radio frequency exposure.

“In every state and country where smart meters have been or may be installed, there is continued opposition from citizen groups concerned with 24/7 radiation emissions deemed by the World Health Organization to be a possible human carcinogen, invasion of privacy for the electronic records the meters record, theft of personal data, infringement of several constitutional rights and compromising of personal and grid cybersecurity,” the Maine coalition says.

Others consider these claims overblown.

Writing at the Huffington Post scientists David Bailey and Jonathan Borwein said that claims that wireless radiation causes problem such as dizziness or memory loss are “absurd.” They said that a 2010 study commissioned by the World Health Organization found only a “very minimal and partially contradictory link” between cell phone use and brain cancer.

“It is also instructive to compare the radiation levels of smart meters with those of other wireless devices,” they wrote. “Smart meters only transmit data for roughly 1.4 seconds per day, at very low wattage. And even if one stands less than one meter (3 feet) from a smart meter when it broadcasts its data, the resulting microwave exposure is 550 times less than standing in front of an active microwave oven, and 1100 times less than holding an active cell phone to one’s ear.”

The American Cancer Society says at its website that it is “very unlikely” that smart meters increase the risk of cancer.

No decision in the Maine case is expected for several months.